NGC 2841

NGC 2841
NGC 2841 imaged by the Hubble Space Telescope
Observation data (J2000 epoch)
ConstellationUrsa Major
Right ascension09h 22m 02.655s[1]
Declination+50° 58′ 35.32″[1]
Redshift0.002130[2]
Heliocentric radial velocity638 km/s[3]
Distance46.0 ± 4.9 Mly (14.1 ± 1.5 Mpc)[4][5]
Apparent magnitude (V)10.1[3]
Characteristics
TypeSAa[2]
Mass7×1010 M☉[6] M☉
Apparent size (V)8.1′ × 3.5′[6]
Notable featuresFlocculent galaxy with LINER nucleus
Other designations
IRAS 09185+5111, UGC 4966, MCG +09-16-005, PGC 26512, CGCG 265-006[3]

NGC 2841 is an unbarred spiral galaxy in the northern circumpolar constellation of Ursa Major. It was discovered on 9 March, 1788 by German-born astronomer William Herschel. J. L. E. Dreyer, the author of the New General Catalogue, described it as, "very bright, large, very much extended 151°, very suddenly much brighter middle equal to 10th magnitude star".[7] Initially thought to be about 30 million light-years distant, a 2001 Hubble Space Telescope survey of the galaxy's Cepheid variables determined its distance to be approximately 14.1 megaparsecs or 46 million light-years.[4] The optical size of the galaxy is 8.1′ × 3.5′.[6]

This is the prototype for the flocculent spiral galaxy,[5] a type of spiral galaxy whose arms are patchy and discontinuous.[8] The morphological class is SAa, indicating a spiral galaxy with no central bar and very tightly-wound arms. There is no grand design structure visible in the optical band, although some inner spiral arms can be seen in the near infrared.[5] It is inclined by an angle of 68° to the line of sight from the Earth, with the major axis aligned along a position angle of 148°.[5]

The properties of NGC 2841 are similar to those of the Andromeda Galaxy.[4] It is home to a large population of young blue stars, and a few H II regions.[9] The luminosity of the galaxy is 2×1010 L☉ and it has a combined mass of 7×1010 M☉.[6] Its disk of stars can be traced out to a radius of around 228 kly (70 kpc). This disk begins to warp at a radius of around 98 kly (30 kpc), suggesting the perturbing effect of in-falling matter from the surrounding medium.[5]

The rotational behavior of the galaxy suggests there is a massive nuclear bulge,[6] with a low-ionization nuclear emission-line region (LINER) at the core; a type of region that is characterized by spectral line emission from weakly ionized atoms.[10] A prominent molecular ring is orbiting at a radius of 7–20 kly (2–6 kpc), which is providing a star-forming region of gas and dust.[6] The nucleus appears decoupled and there is a counter-rotating element of stars and gas in the outer parts of the nucleus, suggesting a recent interaction with a smaller galaxy.[6]

  1. ^ a b Cite error: The named reference Skrutskie2006 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Ann2015 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference ned was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Cepheids was invoked but never defined (see the help page).
  5. ^ a b c d e Cite error: The named reference Zhang2018 was invoked but never defined (see the help page).
  6. ^ a b c d e f g Cite error: The named reference Kaneda2007 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference csel was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Elmegreen-1981-CH3 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Marochnik1995 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference hoetal1997 was invoked but never defined (see the help page).